Rozhen Observation Calendar

Which nights are best for a target over the coming weeks. The astronomy mark (darkness × altitude × Moon) is computed for every night; the weather and the overall mark exist only where Open-Meteo has a forecast (the next four days) or ERA5 history (past nights) — the rest is honestly blank.

Best nights for V1057 Cyg: 03-27 (48), 03-25 (47), 03-26 (47), 03-24 (46), 03-22 (44) — by astronomy; check the weather when the night is within four days.

2031-02-26astronomy score per night — click a bar for that night2031-03-27

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-02-26 Wed	25	—	unknown	04:40–05:30 (good, 0.83 h)	87.3° 10:55	9.79	29%	75.0°
2031-02-27 Thu	26	—	unknown	04:35–05:30 (good, 0.92 h)	87.3° 10:50	9.75	38%	82.2°
2031-02-28 Fri	26	—	unknown	04:30–05:25 (good, 0.92 h)	87.3° 10:45	9.7	48%	89.5°
2031-03-01 Sat	27	—	unknown	04:25–05:25 (good, 1.0 h)	87.3° 10:40	9.66	57%	96.7°
2031-03-02 Sun	28	—	unknown	04:25–05:25 (good, 1.0 h)	87.3° 10:35	9.61	66%	103.7°
2031-03-03 Mon	28	—	unknown	04:20–05:20 (good, 1.0 h)	87.3° 10:35	9.56	75%	110.3°
2031-03-04 Tue	29	—	unknown	04:20–05:20 (good, 1.0 h)	87.3° 10:30	9.52	83%	116.3°
2031-03-05 Wed	29	—	unknown	04:20–05:20 (good, 1.0 h)	87.3° 10:25	9.47	89%	121.4°
2031-03-06 Thu	26	—	unknown	04:15–05:15 (good, 1.0 h)	87.3° 10:20	9.42	95%	125.2°
2031-03-07 Fri	26	—	unknown	04:15–05:15 (good, 1.0 h)	87.3° 10:20	9.38	98%	127.3°
2031-03-08 Sat	26	—	unknown	04:10–05:15 (good, 1.08 h)	87.3° 10:15	9.33	100%	127.2°
2031-03-09 Sun	26	—	unknown	04:10–05:10 (good, 1.0 h)	87.3° 10:10	9.28	99%	125.0°
2031-03-10 Mon	27	—	unknown	04:05–05:10 (good, 1.08 h)	87.3° 10:05	9.23	96%	120.7°
2031-03-11 Tue	27	—	unknown	04:05–05:10 (good, 1.08 h)	87.3° 10:00	9.18	91%	114.7°
2031-03-12 Wed	25	—	unknown	04:00–05:05 (good, 1.08 h)	87.3° 10:00	9.14	84%	107.5°
2031-03-13 Thu	25	—	unknown	04:00–05:05 (good, 1.08 h)	87.3° 09:55	9.09	75%	99.5°
2031-03-14 Fri	26	—	unknown	03:55–05:05 (good, 1.17 h)	87.3° 09:50	9.04	65%	91.0°
2031-03-15 Sat	27	—	unknown	03:50–05:00 (good, 1.17 h)	87.3° 09:45	8.99	54%	82.5°
2031-03-16 Sun	29	—	unknown	03:40–05:00 (good, 1.33 h)	87.3° 09:40	8.94	42%	74.2°
2031-03-17 Mon	33	—	unknown	03:35–05:00 (good, 1.42 h)	87.3° 09:40	8.89	31%	66.5°
2031-03-18 Tue	36	—	unknown	03:20–04:55 (good, 1.58 h)	87.3° 09:35	8.84	21%	60.1°
2031-03-19 Wed	41	—	unknown	03:15–04:55 (good, 1.67 h)	87.3° 09:30	8.78	13%	55.3°
2031-03-20 Thu	43	—	unknown	03:10–04:55 (good, 1.75 h)	87.3° 09:25	8.73	6%	52.7°
2031-03-21 Fri	43	—	unknown	03:10–04:50 (good, 1.67 h)	87.3° 09:25	8.68	2%	52.8°
2031-03-22 Sat	44	—	unknown	03:05–04:50 (good, 1.75 h)	87.3° 09:20	8.63	0%	55.3°
2031-03-23 Sun	44	—	unknown	03:00–04:45 (good, 1.75 h)	87.3° 09:15	8.58	1%	59.8°
2031-03-24 Mon	46	—	unknown	02:55–04:45 (good, 1.83 h)	87.3° 09:10	8.52	4%	65.7°
2031-03-25 Tue	47	—	unknown	02:50–04:45 (good, 1.92 h)	87.3° 09:05	8.47	8%	72.4°
2031-03-26 Wed	47	—	unknown	02:50–04:40 (good, 1.83 h)	87.3° 09:05	8.42	15%	79.7°
2031-03-27 Thu	48	—	unknown	02:45–04:40 (good, 1.92 h)	87.3° 09:00	8.36	22%	87.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-02-26&days=30"
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&days=30&format=csv" -o m31-calendar.csv

One row per night: score_astronomy always, score_weather / score only where a forecast or history exists (null otherwise, with weather_source saying which), best window, dark hours, Moon illumination and separation, transit. 7–60 nights. Errors: 400 with invalid_date or target_unresolved. Results are cached for six hours; calculation version 2026-10-10.1.